Divergent Expression Patterns and Function Implications of Four nanos Genes in a Hermaphroditic Fish, Epinephelus coioides.

Multiple genes have been characterized in several fishes, but the functional implications of their various expression patterns remain unclear. In this study, we identified and characterized four genes from a hermaphroditic fish orange-spotted grouper, . and show divergent expression patterns, and the dynamic expression change of in pituitaries during sex change is associated with testis differentiation and spermatogenesis. and might be germline stem cells (GSCs) and primordial germ cells (PGCs)-specific markers, respectively. Significantly, 3'-untranslated region (UTR) is necessary for PGC specific expression, where a non-canonical "GCACGTTT" sequence is required for miR-430-mediated repression of RNA. Furthermore, grouper Dead end (Dnd) can relieve miR-430 repression in PGCs by associating with a 23 bp U-rich region (URR) in 3'-UTR. The current study revealed the functional association of multiple genes with PGC formation and germ cell development in orange-spotted grouper, and opened up new possibilities for developing biotechnologies through utilizing the associations between and PGCs or between and GSCs in the hermaphroditic fish.